Forging the Thunderbolt

Republic's P-47 Thunderbolt

Originally published in The Dispatch magazine, Volume 19, Number 3, Fall, 1994
edition. If you are interested in subscribing to The Dispatch please write
to The Commemorative Air Force, ATTN: Dispatch Editor, PO Box 62000, Midland, TX
79711-2000 or call (432) 563-1000. Reproduced with permission.

In 1940, Republic Aviation (formerly Seversky Aircraft) began
delivery of 54 P-43 Lancers to the U.S. Army Air Corps. At this time the company had
already started development of a more powerful fighter  the P-44 Rocket, which was
to be powered by a new Pratt & Whitney R-2180 engine of 1,400 horsepower. However,
when the new engine failed, Republic produced another 218 P-43s, with 108 going to the
Nationalist Chinese. This production allowed the company to keep the assembly lines open
until the next design, the P-47, was ready.

The P-47 Thunderbolt was designed around the most powerful engine, radial or inline,
then available  the Pratt & Whitney R-2800 twin-row, air-cooled 18-cylinder
radial, which in early versions gave 2,000 hp. The Thunderbolt also had a
turbo-supercharger mounted in the rear of the fuselage, which allowed the engine to
produce greater power at high altitudes. The resulting design, huge compared to
contemporary fighters such as the P-39 and P-40, incorporated lessons from the early air
war in Europe, including cockpit armor and self-sealing fuel tanks. The plane quickly
became known as the "Jug," as its appearance resembled the milk jug of the day.

The XP-47B first flew on May 6,1941, achieving a top speed of 412 mph and resulting in
an immediate order of the P-47B by the USAAF. By November 1942, the three squadrons of the
56th Fighter Group were operational, equipped with P-47Bs. These squadrons joined the
Eighth Air Force in England in January 1943. The Thunderbolts flew their first mission on
April 8,1943, providing escort for B-17s.

The P-47C was the first model to feature a dropable fuel tank under the belly or wings
of the aircraft, thus allowing the Thunderbolt to escort the bombers further into enemy
territory. Eight inches were later added to the P-47C's length, forward of the firewall,
for better balance and to improve access to engine accessories. About 600 of the C models
were produced in 1943.

The next, and best known version of the Thunderbolt was the P-47D, which had 2,300 hp
and provision for two 150-gallon drop tanks, allowing even greater long range escort
missions. Early versions of the D model continued with the original canopy style and a
high, ridged fuselage, often called a "razorback." To increase the pilot's rear
view, the P-47D-25 introduced a clear "bubbletop" all-around view canopy, with a
cut down rear fuselage. In addition, racks under the wings could hold 10 air-to-ground
rockets, which added extra punch as the Thunderbolt was utilized more in the ground attack
role in 1944 and 1945.

In some "bubbletop" P-47Ds, the loss of the razorback resulted in severe tail
flutter. The P-47D-40 introduced a small dorsal fin in front of the vertical stabilizer
which eliminated the problem.

The final Thunderbolt version to see action in World War II was the P-47N, which was
designed for long-range operations in the Pacific, such as escorting B-29s. A new wing
with four 50 gallon fuel tanks, clipped wingtips and increased span was fitted. With the
new wing, the P-47N could carry up to 1,266 gallons of fuel for a range of 2,350 miles.
The dorsal fin was also enlarged and truncated differently from that on the D model.

Despite being designed for Pacific operations, the first operational P-47Ns were sent
to the 56th Fighter Group in England, but the war in Europe ended before they saw combat

In the Pacific, the 318th Fighter Group on Saipan first took the P-47N into
combat in the spring of 1945. Thunderbolts were sturdy  many returned from missions
with large holes in their structure or even cylinders blown off the engine. Over 15,600
P-47s were built, and in 1.3 million hours of combat flying in World War II, less than 0.7
percent were lost, an exceptionally low figure, especially for a fighter-bomber.

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